18 See, O man, and consider whether what I am saying be true. Have you a body and flesh? I have, you say. For how am I in this place that I now occupy, and how do I move from place to place? How do I hear the words of one who is speaking, but by the ears of my body? How do I see the mouth of him who is speaking, but by the eyes of my body? It is plain then that you have a body, no need is there to trouble one's self about so plain a matter. Consider then another point, consider what it is that acts through this body.
For you hear by means of the ear, but it is not the ear that hears. There is something else within which hears by means of the ear. You see by means of the eye— examine this eye. What! Have you acknowledged the house, and paid no regard to him that inhabites it? Does the eye see by itself? Is it not another that sees by means of the eye? I will not say, that the eye of a dead man, from whose body it is plain the inhabitant has departed, sees not, but any man's eye who is only thinking of something else, sees not the form of the object that is before him.
Look then into your inner man. For there it is rather that the resemblance must be sought for of some three things which are exhibited separately, whose operation is yet inseparable. What then is in your mind? Peradventure if I search, I find many things there, but there is something very near at hand, which is understood more easily. What then is in your soul? Call it to mind, reflect upon it. For I do not require that credit should be given me in what I am about to say; if you find it not in yourself, admit it not.
Look inward then; but first let us see what had escaped me, whether man be not the image, not of the Son only, or of the Father only, but of the Father and the Son, and so consequently of course of the Holy Ghost also. The words in Genesis are, “Let Us make man after Our own image and likeness.” So then the Father does not act without the Son, nor the Son without the Father. “Let Us make man after Our own image and likeness. Let us make,” not, “I will make,” or “You make,” or “Let him make,” but, “Let Us make after,” not “your image,” or “mine,” but, “after Our image.”
Source: Sermons on Selected Lessons of the New Testament (New Advent)